EP3686567A1 - Metallized dielectric waveguide - Google Patents

Abstract

The invention relates to a dielectric conductor arrangement, a method for producing a dielectric conductor arrangement, a fill level radar and a use. The dielectric conductor arrangement 10 has a dielectric conductor core 20 made of a solid. Furthermore, the dielectric conductor arrangement has a coating 30 which, at least in sections, surrounds the entire circumference of the conductor core 20 without a gap and which consists of a thin conductive layer.

Description

Field of the Invention

The invention relates to a dielectric conductor arrangement, a method for producing a dielectric conductor arrangement, a fill level radar and a use.

background

For level measurement or for determining the level, for example in a container, a level radar is used, for example, to measure a certain level of a product, e.g. in the container. For this purpose, radar waves are used, which are generated in a high-frequency unit and emitted by an antenna unit. However, as the frequency increases, it becomes increasingly difficult to transmit the radar waves using a coaxial cable. Therefore, the radar waves and / or microwaves of higher frequencies are in many cases with the help of rigid metallic waveguides that are mixed with a gas - e.g. Air - filled, transferred. However, the lack of mechanical flexibility of these waveguides can restrict the design and / or construction of level radars.

Summary of the invention

It is an object of the invention to provide a conductor arrangement for transmitting radar waves which has mechanical flexibility.

This object is achieved by the subject matter of the independent claims. Further developments of the invention result from the subclaims and the following description.

A first aspect of the invention relates to a dielectric conductor arrangement for the transmission of microwaves. The dielectric conductor arrangement has a dielectric conductor core made of a solid. Furthermore, the dielectric conductor arrangement has a coating which, at least in sections, surrounds the entire circumference of the conductor core without a gap and which consists of a thin conductive layer.

The microwaves comprise at least one frequency range of the radar waves. The microwaves cover a frequency range from 1 to 300 GHz, for example over 60 GHz, for example over 200 GHz. A dielectric conductor core has a dielectric constant ε _r of greater than 1.5, in particular greater than 3. The dielectric conductor core is a solid. The solid is selected so that the microwaves are attenuated only slightly. The solid can for example have a plastic, glass fiber or ceramic or consist of a plastic, glass fiber or ceramic. The solid is flexible. The solid can be designed to have a bending radius of more than 20 cm, in particular less than 4 cm. The solid can be designed so that it is approved for a temperature range up to 250 ° C. Some solids, such as ceramic fiber, can be approved up to 450 ° C.

The coating of the dielectric conductor arrangement consists of a thin conductive layer. This layer surrounds the entire circumference of the conductor core without a gap, at least in sections. The thin conductive layer further contributes to an improvement in wave propagation in the dielectric conductor arrangement. In addition, the conductive layer improves the immunity to interference. On the one hand, this reduces the immissions of interference sources in the conductor core, and on the other hand, the radiation of the microwaves from the conductor core is significantly reduced.

For example, connection points of the dielectric conductor arrangement may have no or no complete conductive layer. The connection points can e.g. be arranged at a joint, in which two line sections are joined together. Junction points can e.g. also be arranged at the beginning and / or at the end of the conductor arrangement, where the microwaves are coupled in and / or out, for example. Techniques which are known in the prior art can be used, for example, for the coupling in and / or out of the microwaves.

The combination of the features mentioned can considerably improve and / or simplify the transmission of microwaves and the handling of a conductor arrangement for the transmission of microwaves. In particular, this can simplify the manufacture of measuring devices for level measurement or for determining the level, for example a level radar. The flexibility of the conductor arrangement, in particular, simplifies its handling. This can contribute to a reduction in the costs for the manufacture and / or maintenance of the conductor arrangement or of devices which comprise this conductor arrangement. Due to the flexibility, the conductor arrangement can also be designed to be bendable and, to a certain extent, even to be able to be wound up.

In one embodiment, the conductor arrangement is set up to have a bending radius of less than 20 cm, in particular less than 4 cm. This further increases the flexibility of the conductor arrangement.

In one embodiment, the dielectric conductor core is essentially cylindrical. This design can further contribute to low microwave attenuation.

In a further embodiment, the dielectric conductor core can be elliptical or rectangular.

In one embodiment, the dielectric conductor core has polytetrafluoroethylene, PTFE, polyether ether ketone, PEEK, polypropylene, PP, polyethylene, PE, ceramic and / or a temperature-resistant glass fiber, or the conductor core consists of at least one of these materials. These materials can advantageously combine good availability of the materials and good transmission properties. At least some of these materials can also be cheaper than, for example, rigid metallic waveguides.

In one embodiment, the coating has a conductivity of greater than 30 · 10 ⁶ S / m, for example greater than 50 · 10 ⁶ S / m. Such a high conductivity can contribute to a further reduction in immissions from sources of interference in the conductor core. On the other hand, this can significantly reduce the radiation of the microwaves from the conductor core.

In one embodiment, the coating has metal, in particular copper, silver, gold, palladium, alloys made from these metals, conductive materials, in particular metallized plastics, graphene, a ductile conductive material and / or a combination of the materials mentioned. The choice of materials for the coating can be determined by material properties such as brittleness, applicability and / or costs.

In one embodiment, the coating has a thickness between 20 μm and 200 μm, in particular between 50 μm and 100 μm. This has proven to be a good compromise between good shielding, simple handling and a good cost structure.

In one embodiment, the coating has conductive lacquer, for example silver conductive lacquer. The conductive lacquer is applied by brushing, spraying, dipping and / or other methods. In experiments, this has proven to be advantageous for the purposes mentioned above. One advantage of this method is that the area between the waveguide and the metallization is always gap-free due to the manufacturing process; As a result, the microwaves are optimally guided in the waveguide.

In one embodiment, the coating is applied to the dielectric conductor core using a thin-film technique.

In one embodiment, the coating is applied to the dielectric conductor core by means of physical vapor deposition, in particular by means of sputter deposition or thermal evaporation, by means of chemical vapor deposition, in particular by means of plasma-assisted chemical vapor deposition, by means of thermal spraying, and / or by means of electroplating, in particular by means of plastic electroplating. The methods mentioned advantageously combine a precise coating with good handling. An advantage of the methods mentioned is that the area between the waveguide and the metallization is always gap-free due to the manufacturing process; As a result, the microwaves are optimally guided in the waveguide.

In one embodiment, the dielectric waveguide can be shaped first and then coated and / or metallized. This can be advantageous, for example, if a waveguide is to be wound up relatively tightly, for example in a spiral.

In one embodiment, the diameter of the dielectric conductor core is selected such that only the basic mode of the microwaves can be propagated in a predefined frequency range. The predefined frequency range may depend on further specifications of the system in which the conductor arrangement is installed. The basic mode of microwaves is also called TE ₁₁ mode or H ₁₁ mode in the round waveguide. In the rectangular waveguide, the basic mode is called TE ₁₀ or H ₁₀ . This embodiment can result in lower signal falsifications, which are caused, for example, by (disruptive) dispersion of the signal. This embodiment can be used particularly advantageously for signal transmission over further distances.

In one embodiment, the coating is also coated and / or coated with a material for shock absorption. This can be particularly advantageous if the conductor arrangement is used outside of a protective housing.

Another aspect of the invention relates to a level radar. The level radar has a high-frequency unit that is set up to generate a microwave signal. In addition, it has an antenna unit that is used to radiate the microwave signal is set up. Furthermore, the fill level radar has a dielectric conductor arrangement as described above and / or below, which is set up to transmit the microwave signal generated by the high-frequency unit to the antenna unit.

The dielectric conductor arrangement can be used, for example, to bridge a distance between the high-frequency unit and the antenna unit. This can be advantageous, for example, in order to achieve a predefined runtime between the two units or, for example, to decouple the temperature of the two units.

In one embodiment, the dielectric conductor arrangement is designed in several parts. The connection of the sections of the dielectric conductor arrangement can e.g. be cut exactly flat or cut at exactly the same angle and surrounded by a metallic or metallized sleeve. The inner diameter of the sleeve can be adapted exactly to the outer diameter of the metallized waveguide. This can result in a gap-free microwave connection, which holds itself due to the fit of the parts. The connection can be designed to be detachable or non-detachable.

In one embodiment, the dielectric conductor arrangement is arranged in a spiral, at least in sections. This is possible because of the flexibility of the conductor arrangement. This can contribute to a reduction in the costs for the manufacture and / or maintenance of the conductor arrangement or of devices which comprise this conductor arrangement.

• Bereitstellen eines dielektrischen Leiterkerns;
• Aufbringen, zumindest abschnittsweise, einer Beschichtung, welche den gesamten Umfang des Leiterkerns spaltfrei umgibt und aus einer dünnen leitfähigen Schicht besteht.

Another aspect of the invention relates to a method for producing a dielectric conductor arrangement as described above and / or below. The process has the following steps:

• Providing a dielectric conductor core;
• Application, at least in sections, of a coating which surrounds the entire circumference of the conductor core without a gap and consists of a thin conductive layer.

The dielectric conductor core can be shaped before and / or after the coating has been applied. The application before the application of the coating can be advantageous, for example, if the waveguide is to be wound relatively closely, for example in a spiral.

• Schneiden eines Endes eines ersten dielektrischen Leiterkerns und eines Endes eines zweiten dielektrischen Leiterkerns in einem vordefinierten Winkel, wobei das Ende des ersten dielektrischen Leiterkerns und das Ende des zweiten dielektrischen Leiterkerns denselben Winkel aufweisen;
• Aneinanderfügen des Endes des ersten dielektrischen Leiterkerns und des Endes des zweiten dielektrischen Leiterkerns in einem Z-Winkel;
• Umhüllen des Endebereichs des ersten dielektrischen Leiterkerns und des Endebereichs des zweiten dielektrischen Leiterkerns mittels einer metallischen oder metallisierten Hülse.

In one embodiment, the conductor arrangement is designed in several parts. The method for producing a multi-part dielectric conductor arrangement has the following further steps:

• Cutting an end of a first dielectric conductor core and an end of a second dielectric conductor core at a predefined angle, the end of the first dielectric conductor core and the end of the second dielectric conductor core having the same angle;
• Joining the end of the first dielectric conductor core and the end of the second dielectric conductor core at a Z angle;
• Enveloping the end region of the first dielectric conductor core and the end region of the second dielectric conductor core by means of a metallic or metallized sleeve.

The predefined angle can be 90 ° or an acute angle, in particular an angle between 30 ° and 60 °, for example between 40 ° and 50 °. The ends of the first and the second dielectric conductor core are cut exactly flat if possible. The ends are then joined together until contact or stop. This can be done before and / or after encasing the end areas by means of the metallic or metallized sleeve. In this way, an essentially gap-free microwave connection can be created, which holds itself due to the fit of the parts. In addition, the connection can also be positively, non-positively and / or materially connected, e.g. glued or and / or fixed with a shrink tube or otherwise.

In one embodiment, the connection between the first dielectric conductor core and the second dielectric conductor core is designed to be detachable. This simplifies the reconfiguration of the conductor arrangement, for example during a repair and / or maintenance. Another aspect of the invention relates to the use of a dielectric conductor arrangement as described above and / or below for the transmission of microwaves in a frequency range from approximately 80 GHz to approximately 300 GHz, in particular approximately 240 GHz

For further clarification, the invention is described on the basis of the embodiments shown in the figures. These embodiments are only to be understood as an example, but not as a limitation.

Brief description of the figures

Fig. 1

eine schematische Skizze eines Füllstandmessgeräts gemäß einer Ausführungsform;

Fig. 2

eine schematische Skizze eines Füllstandmessgeräts gemäß einer weiteren Ausführungsform;

Fig. 3a

eine schematische Skizze einer Verbindung zweier Leiteranordnungen gemäß einer Ausführungsform;

Fig. 3b

eine schematische Skizze einer Verbindung zweier Leiteranordnungen gemäß einer weiteren Ausführungsform;

Fig. 4

ein Verfahren gemäß einer Ausführungsform.

It shows:

Fig. 1

a schematic sketch of a level measuring device according to an embodiment;

Fig. 2

a schematic sketch of a level measuring device according to a further embodiment;

Fig. 3a

a schematic sketch of a connection of two conductor arrangements according to an embodiment;

Fig. 3b

a schematic sketch of a connection of two conductor arrangements according to a further embodiment;

Fig. 4

a method according to an embodiment.

Detailed description of embodiments

Fig. 1 shows a schematic sketch of a level measuring device or level radar 40 according to an embodiment. The fill level radar 40 has a high-frequency unit 42 which is set up to generate a microwave signal. In addition, it has an antenna unit 44 which is set up to emit the microwave signal. The antenna unit 44 can be arranged, for example, by means of a flange on the container with the filling material to be measured. The radio-frequency unit 42 and the antenna unit 44 are connected by means of a dielectric conductor arrangement 10, which is used to transmit the microwave signal generated by the radio-frequency unit 42 to the antenna unit 44 is set up. The microwave signal is emitted, for example, by means of the antenna unit 44, to which an antenna horn 45 can be attached for better bundling. High temperatures, for example up to 250 ° C. or even up to 450 ° C., may be present in the area of the antenna unit 44. Therefore, the conductor arrangement 10 can contribute to the thermal decoupling of antenna unit 44 and high-frequency unit 42. Furthermore, the conductor arrangement 10 is designed to be temperature-resistant to these high temperatures.

Fig. 2 shows a schematic sketch of a level measuring device 40 according to a further embodiment. The fill level radar 40 has a high-frequency unit 42 which is set up to generate a microwave signal. In addition, it has an antenna unit 44 which is set up to emit the microwave signal. In this embodiment, the antenna unit 44 can have a screw-in thread 46. The high-frequency unit 42 and the antenna unit 44 are connected by means of a dielectric conductor arrangement 10, which is set up to transmit the microwave signal generated by the high-frequency unit 42 to the antenna unit 44. The conductor arrangement 10 is designed spirally, for example in order to achieve a predefined propagation time between the high-frequency unit 42 and the antenna unit 44 or, for example, for temperature decoupling. This configuration is possible in particular through the flexibility of the conductor arrangement 10.

Fig. 3a shows a schematic sketch of a connection of two conductor arrangements 10 according to an embodiment. One end 21a of a first dielectric conductor core 20a and one end 21b of a second dielectric conductor core 20b are cut off at a predefined angle w. The end 21a of the first dielectric conductor core 20a and the end 21b of the second dielectric conductor core 20b have the same angle w, in the exemplary embodiment shown 90 °. End regions 22a and 22b of the conductor cores 20a and 20b are encased in a metallic or metallized sleeve 25. The end regions 22a and 22b can, at least in sections, have a coating 30a and 30b. The sleeve 25 can be connected to at least one of the conductor cores 20a and 20b or to the coating 30a and 30b in a form-fitting, force-fitting and / or material-locking manner, for example
glued or and / or fixed with a shrink tube or otherwise. The connection can be designed to be detachable or non-detachable.

Fig. 3b shows a schematic sketch of a connection of two conductor arrangements 10 according to a further embodiment. The Fig. 3b differs from Fig. 3a by the angle w, which at Fig. 3b is an acute angle. The conductor cores 20a and 20b have the same angle w.

Fig. 4 15 shows a flow diagram 50 of a method according to an embodiment. In step 51, a dielectric conductor core 20 (see figures above) is provided as specified in the above description. In a step 52, a coating 30 is applied at least in sections. The coating 30 surrounds the entire circumference of the conductor core 20 without a gap and consists of a thin conductive layer. The dielectric conductor core can be brought into shape, for example in a spiral shape, before and / or after the application of the coating.

In addition, it should be pointed out that "comprising" and "having" do not exclude other elements or steps, and the indefinite articles "a" or "an" do not exclude a large number. Furthermore, it should be pointed out that features or steps that have been described with reference to one of the above exemplary embodiments can also be used in combination with other features or steps of other exemplary embodiments described above. Reference signs in the claims are not to be regarded as restrictions.

List of reference numbers

10th

dielectric conductor arrangement

20, 20a, 20b

dielectric conductor core

21a, 21b

The End

22a, 22b

End range

25th

Sleeve

30, 30a, 30b

Coating

40

Level measuring device, level radar

42

Radio frequency unit

44

Antenna system

45

Antenna horn

46

Screw-in thread

47

conical area

50

flow chart

51, 52

steps

Claims (15)

Dielectric conductor arrangement (10) for the transmission of microwaves, comprising: - A dielectric, conductor core (20) made of a solid; and - A coating (30) which at least in sections surrounds the entire circumference of the conductor core (20) without a gap and which consists of a thin conductive layer. Dielectric conductor arrangement (10) according to Claim 1,
wherein the conductor arrangement (10) is set up to have a bending radius of less than 20 cm, in particular less than 4 cm. Dielectric conductor arrangement (10) according to Claim 1 or 2,
wherein the dielectric conductor core (20) has polytetrafluoroethylene, PTFE, polyether ether ketone, PEEK, polypropylene, PP, polyethylene, PE, ceramic and / or a temperature-resistant glass fiber or consists of at least one of these materials. Dielectric conductor arrangement (10) according to one of the preceding claims,
wherein the coating (30) has a conductivity of greater than 30 · 10 ⁶ S / m, for example greater than 50 · 10 ⁶ S / m. Dielectric conductor arrangement (10) according to Claim 4,
wherein the coating (30) has metal, in particular copper, silver, gold, palladium, alloys of these metals, conductive materials, in particular metallized plastics, graphene, a ductile conductive material and / or a combination of the materials mentioned. Dielectric conductor arrangement (10) according to Claim 4,
wherein the coating (30) has a thickness between 20 microns and 200 microns, in particular between 50 microns and 100 microns. Dielectric conductor arrangement (10) according to one of the preceding claims,
wherein the diameter of the dielectric conductor core (20) is selected such that only the basic mode of the microwaves can be propagated in a predefined frequency range. Dielectric conductor arrangement (10) according to one of the preceding claims, wherein the coating (30) is further coated and / or coated with a material for shock absorption. Level radar (40), comprising: a high-frequency unit (42) set up to generate a microwave signal, an antenna unit (44) set up to emit the microwave signal, and a dielectric conductor arrangement (10) according to one of the preceding claims, set up to transmit the microwave signal generated by the high-frequency unit (42) the antenna unit (44). Level radar (40) according to claim 9,
wherein the dielectric conductor arrangement (10) is made in several parts. Level radar (40) according to claim 9 or 10,
wherein the dielectric conductor arrangement (10) is arranged at least in sections in a spiral. Method for producing a dielectric conductor arrangement (10) according to one of Claims 1 to 8, comprising the steps: - Providing a dielectric conductor core (20); - Applying, at least in sections, a coating (30) which surrounds the entire circumference of the conductor core (20) without a gap and consists of a thin conductive layer. Method for producing a multi-part dielectric conductor arrangement (10) according to Claim 12, with the further steps: - Cutting an end (21a) of a first dielectric conductor core (20a) and an end (21b) of a second dielectric conductor core (20b) at a predefined angle (w), the end (21a) of the first dielectric conductor core (20a) and that End (21b) of the second dielectric conductor core (20b) have the same angle (w); - joining the end (21a) of the first dielectric conductor core (20a) and the end (21b) of the second dielectric conductor core (20b) at a Z angle (w); - Enveloping the end region (22a) of the first dielectric conductor core (20a) and the end region (22b) of the second dielectric conductor core (20b) by means of a metallic or metallized sleeve (25). The method of claim 12 or 13,
wherein the connection between the first dielectric conductor core (20a) and the second dielectric conductor core (20b) is designed to be detachable. Use of a dielectric conductor arrangement (10) according to one of Claims 1 to 8 for the transmission of microwaves in a frequency range from approximately 80 GHz to approximately 300 GHz, in particular approximately 240 GHz.

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